Our research program is designed to understand the molecular logic responsible for the correct spatial and temporal expression of choline acetyltransferase (ChAT). We also propose to study the biological significance of ChAT regulation by relating molecular features of ChAT expression to animal behavior. Using genomic clones containing putative regulatory sequences for ChAT, we will continue to map the important cis DNA regulatory elements in P-element transformed Drosophila by observing the expression pattern of a beta-galactosidase reporter gene. We are particularly interested in elements which our initial studies have indicated may be spatially and/or temporally specific for subsets of cholinergic neurons. We will test several potential mechanisms responsible for the differential expression patterns we have seen. Fusion genes of modified ChAT cDNA and ChAT regulatory DNA (and in some cases the reporter gene) will also be incorporated into transgenic animals and analyzed for their ability to produce appropriate levels of ChAT activity as well as correct cellular and subcellular distribution. We also plan to investigate the behavioral consequences of restoring wild type ChAT in animals with a mutant ChAT genetic background. By analyzing behaviors, of both adult and larval stage Drosophila, we will attempt to define specific subsets of cholinergic neurons which play a critical role in mediating a particular behavior. "Rescued cells" will be identified using immunocytochemical and/or in situ hybridization techniques. Our studies will provide basic information which could have relevance to protocols now being developed to genetically engineer cells for neurotransmitter replacement therapies in neurodegenerative diseases such as Alzheimer's.